Lightweight helmets for head protection during bicycle falls and accidents have evolved continuously and undergone numerous improvements in recent years. One particular area of refinement has been in the fitting and stabilizing of the helmet on a bicycle rider's head.
The sport of mountain biking has grown increasingly popular in recent years. This activity involves riding specially designed bicycles with heavy duty frames and components on unpaved roads, trails, and rough terrain. Conventional bicycle helmets typically are used for protection from falls. The bouncing, bumping, and jarring associated with such riding, however, exacerbates the fit problem of excessive helmet movement on the rider's head.
One solution to the fit problems of a helmet on a rider's head has been to utilize the undercut portion beneath the occipital region of the rider's head to stabilize the helmet. There are several apparent reasons for this. The first is that the process used to mold a one piece shell of a helmet can not easily tolerate a negative draft angle without prohibitably expensive multi-part molds to allow removal of the helmet after molding. The second reason concerns the difficulty or impossibility of the rider fitting the helmet over his or her head if the helmet contains a substantial inner curve to match the undercut portion of the back of the head. Additionally, without adjustment functionality, the helmet would have to fit the user perfectly, requiring many more shapes and sizes of helmets.
While articulated helmet band constructions have been developed to bias the occipital region of the wearer's head against the main shell portion of the helmet, the lightweight materials, such as nylon, required to provide resilient, strong, and flexible constructions are quite expensive, and too rigid to feel comfortable in a fit belt around the head. More economical, commodity materials such as polyethylene are soft and extremely flexible, but are weak and can creep under loaded conditions.
What is needed is a lightweight, economical helmet band construction that is constructed of more economical commodity materials and yet exhibits the strength and reliability of more expensive engineered materials.